Winner Of The Race Engine Challenge

General engine tech -- Drag Racing to Circle Track

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Re: Winner Of The Race Engine Challenge

Post by randy331 »

Steve.k wrote: Mon Oct 15, 2018 12:27 am Truck pulling seems way harder on equipment than I've ever seen. Drag racing compared to dyno runs. Nope.
What makes a pull on the dyno harder on the engine than a pass at the dragstrip ?

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Re: Winner Of The Race Engine Challenge

Post by Truckedup »

randy331 wrote: Mon Oct 15, 2018 8:39 am
Steve.k wrote: Mon Oct 15, 2018 12:27 am Truck pulling seems way harder on equipment than I've ever seen. Drag racing compared to dyno runs. Nope.
What makes a pull on the dyno harder on the engine than a pass at the dragstrip ?

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Truck pulling lasts about 20 seconds at wide open throttle...Some run vehicles at longer periods on chassis dynos.. My vintage LSR race bike junk is run at full power for at least 30 seconds for durability testing...
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Re: Winner Of The Race Engine Challenge

Post by Steve.k »

Well talked with dyno guy and he tells me im right and wrong. :shock: He says the dyno pulls the engine as hard as in vehicle. However its a controlled pull. (ie) no dust,slick surface or any track related issues that can give a shock to engine. I did reiterate the discussion here and mentioned the dyno queen scenario. He says no such thing. If a engine blows up on dyno he figured it would blow up sooner in vehicle. Harder to catch so to speak. So Randy you are correct I'd say. I mentioned to him about this block i bought and he figured likely got to hot during the event with being grouted. They require alot of cool down time to stay safe. We seen this with my grouted engines.
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Re: Winner Of The Race Engine Challenge

Post by CamKing »

As for the "Dyno Queen" term.
Maybe this will make it easier for some of you to understand.
The Rules for the REC, are to try and keep the engine representative of a engine that will run over 3,000 miles, not under 300.
Anyone that has spent a lot of time building circle track engines knows that you can build a qualifying engine, to make more power then an engine that has to live for 700 miles.

Shoving a ton of compression into the engine, to the point the tune has to be perfect to live, or running a cam that wears out the springs in 50 miles, is not representative of a Street/Strip engine that you would sell to a customer.
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Re: Winner Of The Race Engine Challenge

Post by pamotorman »

if dyno testing is not as hard on a engine as racing why do the big race teams have dyno programs to duplicate track conditions that run the engine for up to 24 hours on the dyno.
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Re: Winner Of The Race Engine Challenge

Post by Bazman »

I meant no disrespect to what you guys have done and have huge admiration for your work.

The term "dyno queen" was not aimed at anyone specifically, more at the possibility of knock sensors picking up slight but "tolerable" detonation at the lower end of the rpms tested that would become intolerable at even lower rpms where the engine (supposed to be hot street) would in real world street conditions often be.

Of course in the real world, you'd knock timing back down there so it would not in fact be an issue. I should not have said that and it deflected from what I was asking. My apologies
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Re: Winner Of The Race Engine Challenge

Post by Bazman »

CamKing wrote: Mon Oct 15, 2018 10:56 am As for the "Dyno Queen" term.
Maybe this will make it easier for some of you to understand.
The Rules for the REC, are to try and keep the engine representative of a engine that will run over 3,000 miles, not under 300.
Anyone that has spent a lot of time building circle track engines knows that you can build a qualifying engine, to make more power then an engine that has to live for 700 miles.

Shoving a ton of compression into the engine, to the point the tune has to be perfect to live, or running a cam that wears out the springs in 50 miles, is not representative of a Street/Strip engine that you would sell to a customer.
You said it much more eloquently than I did. I had picked up on the fact the engine's were supposed to represent what a hot street motor could be an dby implication that means last a while. Having said that, if I was involved in a competition like that and there was no endurance test, I'm sure I'd try to win vs trying to have the engine with the least amount of wear at the end of it. :lol:
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Re: Winner Of The Race Engine Challenge

Post by echosixmike »

Dynos don't have driveline shock loads, engine braking decellerations, dynamic chassis loads in 3 dimensions causing oil control problems, as well as potentially using the engine as a stressed member of the vehicle. Dynos are a controlled environment, the track is not. S/F....Ken M
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Re: Winner Of The Race Engine Challenge

Post by houser45 »

Have you ever stood in the infield and watched a dirt oval circle track engine bounce through the holes on a rough race track spin the tires and then become hooked up again ? There is no way even close but an engine Dyno is as hard on those conditions plus you have oil control issues with racing on the track.
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Re: Winner Of The Race Engine Challenge

Post by Steve.k »

I beleive Porsche designed a dyno that simulated all the attributes of the track. Even negative g's like that of deceleration. So yes they are very similar to track conditions.Heres what Ford did in 60's. https://m.youtube.com/watch?v=NxP__UPj7L8. Mind you we getting a little off topic.
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Re: Winner Of The Race Engine Challenge

Post by digger »

On a chassis dyno underhood temps seem to get hotter than on the road due to reduced airflow.
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Re: Winner Of The Race Engine Challenge

Post by Keith Morganstein »

Article on Jack Barna's 376 cu/in Mopar, the Winner of the inline valve class

https://www.enginebuildermag.com/2018/1 ... id=2293765
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Re: Winner Of The Race Engine Challenge

Post by nitro2 »

houser45 wrote: Tue Oct 16, 2018 8:11 am Have you ever stood in the infield and watched a dirt oval circle track engine bounce through the holes on a rough race track spin the tires and then become hooked up again ? There is no way even close but an engine Dyno is as hard on those conditions plus you have oil control issues with racing on the track.
Right, dynos such as most people use, aren't nearly as hard on an engine as what you described, nor a bouncing truck/tractor during a pull. Plus lots of oval track engines blow up at high revs with the throttle shut at the end of the straight.

Also in some other types of racing, such as 2 stroke marine racing, there can be weird on/off throttle scenarios that cause engine failure in a race, but there is seemingly no way to duplicate it on the dyno (the engine on/off throttle scenario can be duplicated, but not the failure).
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Re: Winner Of The Race Engine Challenge

Post by MadBill »

nitro2 wrote: Wed Nov 07, 2018 11:14 am...Also in some other types of racing, such as 2 stroke marine racing, there can be weird on/off throttle scenarios that cause engine failure in a race, but there is seemingly no way to duplicate it on the dyno (the engine on/off throttle scenario can be duplicated, but not the failure).
One could see how this might happen with pre-mix: closed throttle = no air = no fuel = no lube... :-k Not with oil injection of course.
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Re: Winner Of The Race Engine Challenge

Post by nitro2 »

MadBill wrote: Wed Nov 07, 2018 2:47 pm
nitro2 wrote: Wed Nov 07, 2018 11:14 am...Also in some other types of racing, such as 2 stroke marine racing, there can be weird on/off throttle scenarios that cause engine failure in a race, but there is seemingly no way to duplicate it on the dyno (the engine on/off throttle scenario can be duplicated, but not the failure).
One could see how this might happen with pre-mix: closed throttle = no air = no fuel = no lube... :-k Not with oil injection of course.
Not that kind of failure.

Detonation failure. Closing/closed throttle 2 stroke detonation. This type of detonation is common, even on mundane stuff, but on higher powered applications is more intense. "Detonation" is a bit generic, can be HCCI. Generally very brief, but it doesn't take much to cause damage on a 2 stroke. Opening the throttle at just the wrong time after closing it can be worse yet.
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